The CD4/CD8 lineage decision: integration of signalling pathways

An immature CD4(+)CD8(+) thymocyte mn differentiate into a functionally specialized CD4(+) or CD8(+) T cell. The molecular mechanisms underlying this CD4/CD8 lineage choice are poorly understood. Recent evidence suggests that thymocytes are sensitive to subtle variations in signal intensity and that lineage choice might be the consequence of the integration of signals emanating from multiple pathways.